Building a computer out of 555 chips

[M. Eric Carr] came up with an interesting build for the 555 contest earlier this year, and we’re pretty sure that it would have kicked the winner of the complex category off the throne if it were completed. Although it’s a few months late, we’re happy to feature at least part of his 555-based computer on Hack A Day.

[M. Eric Carr] started off implementing Boolean logic with a 555. After building a universal gate, he moved onto putting one bit of memory in a single 555. This design uses the 555 as a latch and is one of the craziest off-spec uses of a 555. While fitting 24 bits of memory on 5 large bread boards may seem like a waste, it’s a far cry from the square feet or acres of other computer builds we’ve seen.

From the post on the 555-based memory, [M. Eric Carr] says a completed design of his computer could be up and working this summer. It’s already August, so we’re hoping he’s still working on his design. Check out the video of the memory below.

Thanks for the writeup! Please bear with my poor little webserver if you follow the link; it’s not used to this kind of traffic. The video is hosted at YouTube, though, so it should be good to go.
I’m still working on the design, though a lot more slowly than I had planned, due to other projects that have come up. I’d be happy to answer any questions about the project; email me at eric @ (the website domain in the first link).

Many sites using cloudflare seem to just randomly time out on me, dunno if it’s a problem with being overseas from their servers or some other routing issue, but they do it a lot. Work one second, time out the next.

I’m not sure what the final operational speed will be, although my guess would be somewhere in the 100kHz-to-1MHz range in “high speed” mode (555s aren’t designed for very high speeds.) More likely, I’d run it at slower speed (a few Hz) to show the operations as they run.
I doubt it will ever run Contiki, if it needs 40kB of ROM. Right now, the address bus is four bits, limiting the design to 16 words of memory. Realistically, I might hope to add a few numbers. More ambitious would be to make an 8-bit machine with 256 bytes of memory. That might be able to make a very basic webserver (with an Arduino handling everything but the applications layer.)
For something that large, though, I’d need a more efficient way of building large components. EDA for 555 logic design, maybe? 8-)

Putting 100 breadboards into a CNC machine and give it a big stack of 555’s and a km or so of wire might speed things up a little. (or something like the auto wire wraping machine that was featured on here a while back)
Maybe several all set to the same frequency but offset by a much higher frequency to enable you to create really high frequencies for out putting video possibly?
I wonder how fast 555’s go if they are really pushed hard if they are liquid nitrogen cooled extra